Curt get some cup added on that prop. porpoising happens when the prop lifts the nose and loses bite an it drops and then starts all over again. I doubt bery much youre experiencing blowout prob mean cavitaion or ventilation, If your pants arent brown it isnt blow out. this happens when the boat and prop lose bite all together and the boat is totally uncontrollable no steering no forward thrust just sliding out of control until it eventually stops Usually at around 85 with a stock torque master and 80 with a std. I guarrentee you will remember that. the boat could even turn sideways and flip thats why over 85 mph you have to go to a sportmaster lower it will hold at a faster speed. \
Now cavitation is when the water stream has tiny bubbles in it and cavitates and actually boils the finish off the prop and lower loss of top speed is kinda the only problem.
Now Im guessing you have a ventilation problem where the rpms go up in the hole shot like a dragster burning rubber then all of a sudden the prop grabs and u get some forward movement. Youre gettin a lot of air in the water stream and the prop isnt biting . you hear a distinct rpm rise and then it drops. Thats a cupping issue or youre too high.
Your settup needs attention You deff arent geting all you can from that setup u have now. height, right prob and maybe a set of wedges to get you tucked under more for the hole shot.